1. Field of the Invention
The present invention is concerned with steering systems for zero turning radius mowers. More particularly, it is concerned with a dual steering system which preferably enables steering to be accomplished by the operator using his or her aims, legs or both to provide steering input to a zero turning radius mower.
2. Description of the Prior Art
Mowing of vegetation on tracts of lands is a task familiar to many. Over the years, new systems have been developed for accomplishing this chore, from reel-type push mowers to motorized walk-behind mowers, and eventually mowers which are self-propelled and carry the operator, known as riding lawn mowers. Zero-turn riding lawn mowers (herein “zero turning radius mowers”) represent an improvement in mower systems which are now well known to the public, and their development is usually traced to the early or mid 1960's. Zero turning radius mowers are ridden by the operator and provided with a drive and steering system which enables the mower to be driven and steered in tight turns and even to spin about a vertical axis positioned equidistant two drive wheels. Examples of zero turning radius mowers and steering systems therefor are shown in U.S. Pat. Nos. 4,395,865, 4,429,515 and 5,644,903, the disclosures of which are incorporated herein by reference in their entirety. Zero turning radius mowers thus present significant advantages over traditionally steered riding lawn mowers in that vegetation can be cut in a complete circle around trees, bushes or other vegetation not possible in a single pass by traditional riding lawn mowers having the steered wheels spaced forwardly or rearwardly of the driven wheels.
Zero turning radius mowers generally have at least four wheels, two of the wheels being laterally spaced independently driven drive wheels, and a cutting deck which includes one or more rotating cutting blades for cutting grass or other vegetation. An engine, typically an internal combustion engine, supplies power to both rotate the cutting blade or blades and to propel the driven wheels independently of one another. zero turning radius mower. Typically, the zero turning radius mower has left and right drive wheels which are parallel and spaced apart, and each is rotated independently of the other in forward or backward directions by respective hydraulic motors. Steering and speed control is effected by respective left and right manually operated control levers operatively coupled to their respective hydraulic motors. The operator propels the zero turning radius mower in the desired path by forward and backward movement of these control levers; for example, if the operator wishes to have the zero turning radius mower spin or pivot in a clockwise direction about a vertical axis midway between the left and right drive wheels, the operator grasps the left control lever with his or her left hand and pushes the lever forward, while at the same time grasping the right control lever with his or her right hand pulling the right lever rearwardly.
Undoubtedly, zero turning radius mowers represent a significant advance in mowing technology. It has been recognized, however, that there are certain drawbacks. For example, during prolonged mowing, the operator's arms may experience fatigue. Heretofore, the solution to this drawback has been to provide a joystick or a steering wheel. This solution may provide some additional comfort, but does not address problems considered and solved by the present invention.